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Convection
Beginner
Heat carried by moving fluid.
Heat transported by bulk motion of a fluid: warm fluid rises, cool sinks. It gives breezes and ocean currents.
A radiator heats a room by convection currents.
Not possible in a solid or vacuum.
In more detail
Convection is heat transfer by the bulk motion of a fluid. Warmer fluid rises because it is less dense, carrying heat with it, and cooler fluid sinks.
Real-world uses
- Radiators heat rooms by convection of air.
- Ocean currents transport heat around the planet.
- Warm air rises from a radiator and cools near a window, which sets up a circulation pattern in a room.
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Frequently asked questions
Why are heaters placed low in a room?
Because warm air rises, so the heat circulates through the room more effectively when heaters are low.
Is convection heat transfer?
Yes, it moves energy by carrying hot matter from one place to another.
Why do heaters sit low in a room?
Warm air rises, so the heat from a low heater spreads through the room by convection more evenly.
Related topics in Heat & Thermodynamics
Triple and critical points · Conduction · Thermal resistance · Radiation · Stefan–Boltzmann law · Newton's law of cooling